Montreal, Canada (CNN) -- Canadians expressed outrage Thursday after the release of Guy Turcotte, a cardiologist who in 2009 confessed to killing his children as they slept in their beds.

What many wanted to know was how a father who stabbed his children dozens of times could be free after 46 months of confinement. Those voices echo the grief of Turcotte's ex-wife, Dr. Isabelle Gaston, the mother of 5-year-old Olivier and 3-year-old Anne-Sophie.

As Gaston pored over her children's autopsy reports, she wished she had no idea what they meant. But as a physician and a coroner, she knows it's true: Her children suffered a long, gruesome death.

"I knew it was not a short death. You know, my little boy received 20 stabs of a knife, he had seven marks of defense," she told CNN in an interview at her home before Turcotte's full release. "He had no wound that was the one that gave him death," she added, trying to hold back tears.

"My little girl, she had 19 wounds, maybe she was luckier? Because she had one that was more mortal than the other. But she felt 19 shots, that's for sure," Gaston said.

Turcotte confessed to killing his children in February 2009 but a year later a Canadian jury failed to convict him of the murders, finding him not criminally responsible due to mental illness.

At trial, Turcotte testified that he was distraught over his crumbling marriage and snapped, insisting he blacked out and doesn't remember killing his children.

The jury believed the testimony of two psychiatrists paid for by his defense. They testified that Turcotte could not have known what he was doing when he repeatedly stabbed his children.

"Why don't I accept that he is mentally ill is when I look at the facts," Gaston said. "We have a person that is a cardiologist that never had a psychiatric incident, not at all. I have trouble to understand how someone in five hours or six hours will do an interview of someone and have a conclusion that he is not a danger to society or is mentally insane."

Even the Canadian government has weighed in, calling Turcotte's release "unacceptable."

"We believe that Isabelle Gaston does not deserve to live in fear of her children's killer and neither do victims of similar crimes across Canada," said James Moore, a federal cabinet minister.

The Conservative government of Prime Minster Stephen Harper is drafting legislation to make it more difficult for mentally ill offenders to be released from psychiatric facilities, but the pending legislation is not expected to influence Turcotte's case.

In fact, Turcotte told the psychiatric review board that released him that he is looking forward to leading a normal life in the future and hopes to practice medicine and have children again.

"To know that my children faced the person that they should have trusted the most and they were left by themselves to die. No one holding their hand," Gaston said. "I struggle, OK, I struggle all the days, every day of my life and I think till I die I will struggle."